Artificial stone molded body and process for fabrication thereof

Abstract

Disclosed is a process for fabricating an artificial stone molded body by mixing an inorganic filler such as alumina with a resin binder and polymerizing and curing the mixture. A high-viscosity syrup formed by preliminarily polymerizing a polyol polyallyl carbonate with an ethylenically saturated monomer is used as the resin binder and is mixed with the inorganic filler. According to this process, the polymerization is completed in a short time and the internal stress in the molded body is moderated. The molded body fabricated according to this process is excellent in Barcol hardness, pencil hardness, taper abrasion, Sharpy impact strength, flexural strength, heat resistance and chemical resistance.

What is claimed is: 
     
       1. A process for the fabrication of an artificial stone molded body, which comprises preliminarily polymerizing 20 to 95% by weight, based on the total monomers, of a polyol polyallyl carbonate with 5 to 80% by weight, based on the total monomers, of an ethylenically unsaturated monomer having a higher polymerization speed than that of the polyol polyallyl carbonate monomer to prepare a high-viscosity syrup, mixing with said syrup 20 to 80% by weight of an inorganic filler and a catalytic amount of radical polymerization initiator to prepare a composition, filling the composition into a mold, and heating the composition in the mold to polymerize the composition. 
     
     
       2. A process according to claim 1, wherein the inorganic filler is a fine powder selected from the group consisting of silica and aluminum trihydrate and has a particle size of 1 to 30μ. 
     
     
       3. A process according to claim 1, wherein the high-viscosity syrup has a viscosity of 400 to 2000 cps. 
     
     
       4. A process according to claim 1, wherein the polyol polyallyl carbonate is diethylene glycol bisallyl carbonate. 
     
     
       5. A process according to claim 1, wherein the ethylenically unsaturated monomer is an acrylic acid ester or a methacrylic acid ester. 
     
     
       6. A process according to claim 5, wherein the ethylenically unsaturated monomer is methyl methacrylate. 
     
     
       7. A process according to claim 4, wherein the ethylenically unsaturated monomer is an acrylic acid ester or a methacrylic acid ester. 
     
     
       8. A process according to claim 4, wherein the ethylenically unsaturated monomer is methyl methacrylate. 
     
     
       9. A process according to claim 1, wherein the composition is heated in the mold at a temperature of 50° C. to 120° C. for 3 to 8 hours to polymerize the composition. 
     
     
       10. A process for the fabrication of an artificial stone molded body, which comprises preliminarily polymerizing 20 to 95% by weight, based on the total monomers, of diethylene glycol bisallyl carbonate with 5 to 80% by weight, based on the total monomers, of methyl methacrylate to prepare a syrup having a viscosity of 400 to 2000 cps, mixing with said syrup 20 to 80% by weight of an inorganic filler selected from the group consisting of silica and aluminum trihydrate and having a particle size of 1 to 30μ and a catalytic amount of radical polymerization initiator to prepare a composition, filling the composition into a mold, and heating the composition in the mold to polymerize the composition. 
     
     
       11. An artificial stone formed body which comprises a composition comprising (i) 20 to 80% by weight of a three-dimensionally crosslinked binder resin consisting essentially of 20 to 95% by weight, based on the total monomers, of diethylene glycol bisallyl carbonate and 5 to 80% by weight, based on the total monomers, of methyl methacrylate and (ii) 80 to 20% by weight of an inorganic filler selected from the group consisting of silica and aluminum trihydrate and having a particle size of 1 to 30μ, said composition being obtained by mixing a high-viscosity syrup of a preliminary polymerization product of the ethylene glycol bisallyl carbonate and methyl methacrylate with the inorganic filler, filling the mixture in a mold and polymerizing the mixture in the mold. 
     
     
       12. An artificial stone formed body which is obtained by the process of claim 1. 
     
     
       13. A process according to claim 1, wherein the high-viscosity syrup has a viscosity of 500 to 1000 cps. 
     
     
       14. A process according to claim 1, wherein the amount of the ethylenically unsaturated monomer is 25 to 75% by weight, based on the total monomer. 
     
     
       15. An artificial stone body formed according to the process of claim 8, wherein the amount of methyl methacrylate is from 25 to 75% by weight, based on the total monomers.